Maximizing dynamic range in resonant sensing

ABSTRACT

A system may include a resistive-inductive-capacitive sensor configured to sense a physical quantity, and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to measure one or more resonance parameters associated with the resistive-inductive-capacitive sensor and indicative of the physical quantity and, in order to maximize dynamic range in determining the physical quantity from the one or more resonance parameters, dynamically modify, across the dynamic range, either of reliance on the one or more resonance parameters in determining the physical quantity or one or more resonance properties of the resistive-inductive-capacitive sensor.

FIELD OF DISCLOSURE

The present disclosure relates in general to electronic devices withuser interfaces, (e.g., mobile devices, game controllers, instrumentpanels, etc.), and more particularly, resonant phase sensing ofresistive-inductive-capacitive sensors for use in a system formechanical button replacement in a mobile device, and/or other suitableapplications.

BACKGROUND

Many traditional mobile devices (e.g., mobile phones, personal digitalassistants, video game controllers, etc.) include mechanical buttons toallow for interaction between a user of a mobile device and the mobiledevice itself. However, such mechanical buttons are susceptible toaging, wear, and tear that may reduce the useful life of a mobile deviceand/or may require significant repair if malfunction occurs. Also, thepresence of mechanical buttons may render it difficult to manufacturemobile devices to be waterproof. Accordingly, mobile devicemanufacturers are increasingly looking to equip mobile devices withvirtual buttons that act as a human-machine interface allowing forinteraction between a user of a mobile device and the mobile deviceitself. Similarly, mobile device manufacturers are increasingly lookingto equip mobile devices with other virtual interface areas (e.g., avirtual slider, interface areas of a body of the mobile device otherthan a touch screen, etc.). Ideally, for best user experience, suchvirtual interface areas should look and feel to a user as if amechanical button or other mechanical interface were present instead ofa virtual button or virtual interface area.

Presently, linear resonant actuators (LRAs) and other vibrationalactuators (e.g., rotational actuators, vibrating motors, etc.) areincreasingly being used in mobile devices to generate vibrationalfeedback in response to user interaction with human-machine interfacesof such devices. Typically, a sensor (traditionally a force or pressuresensor) detects user interaction with the device (e.g., a finger presson a virtual button of the device) and in response thereto, the linearresonant actuator may vibrate to provide feedback to the user. Forexample, a linear resonant actuator may vibrate in response to userinteraction with the human-machine interface to mimic to the user thefeel of a mechanical button click.

However, there is a need in the industry for sensors to detect userinteraction with a human-machine interface, wherein such sensors provideacceptable levels of sensor sensitivity, power consumption, dynamicrange, and size.

SUMMARY

In accordance with the teachings of the present disclosure, thedisadvantages and problems associated with sensing of human-machineinterface interactions in a mobile device may be reduced or eliminated.

In accordance with embodiments of the present disclosure, a system mayinclude a resistive-inductive-capacitive sensor configured to sense aphysical quantity, and a measurement circuit communicatively coupled tothe resistive-inductive-capacitive sensor and configured to measure oneor more resonance parameters associated with theresistive-inductive-capacitive sensor and indicative of the physicalquantity and, in order to maximize dynamic range in determining thephysical quantity from the one or more resonance parameters, dynamicallymodify, across the dynamic range, either of reliance on the one or moreresonance parameters in determining the physical quantity or one or moreresonance properties of the resistive-inductive-capacitive sensor.

In accordance with embodiments of the present disclosure, a method mayinclude measuring one or more resonance parameters associated with aresistive-inductive-capacitive sensor and indicative of a physicalquantity sensed by the resistive-inductive-capacitive sensor and, inorder to maximize dynamic range in determining the physical quantityfrom the one or more resonance parameters, dynamically modifying, acrossthe dynamic range, either of reliance on the one or more resonanceparameters in determining the physical quantity or one or more resonanceproperties of the resistive-inductive-capacitive sensor.

Technical advantages of the present disclosure may be readily apparentto one having ordinary skill in the art from the figures, descriptionand claims included herein. The objects and advantages of theembodiments will be realized and achieved at least by the elements,features, and combinations particularly pointed out in the claims.

It is to be understood that both the foregoing general description andthe following detailed description are examples and explanatory and arenot restrictive of the claims set forth in this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments and advantagesthereof may be acquired by referring to the following description takenin conjunction with the accompanying drawings, in which like referencenumbers indicate like features, and wherein:

FIG. 1 illustrates a block diagram of selected components of an examplemobile device, in accordance with embodiments of the present disclosure;

FIG. 2 illustrates a mechanical member separated by a distance from aninductive coil, in accordance with embodiments of the presentdisclosure;

FIG. 3 illustrates selected components of an inductive sensing systemthat may be implemented by a resonant phase sensing system, inaccordance with embodiments of the present disclosure;

Each of FIGS. 4A-4C illustrates a diagram of selected components of anexample resonant phase sensing system, in accordance with embodiments ofthe present disclosure;

FIG. 5 illustrates a diagram of selected components of an exampleresonant phase sensing system implementing time-division multiplexedprocessing of multiple resistive-inductive-capacitive sensors, inaccordance with embodiments of the present disclosure;

FIG. 6 illustrates graphs depicting example amplitude-versus-frequencyand phase-versus-frequency characteristics of a resonant sensor, inaccordance with embodiments of the present disclosure; and

FIG. 7 illustrates a diagram of selected components of an exampleresonant phase sensing system, in accordance with embodiments of thepresent disclosure.

DETAILED DESCRIPTION

FIG. 1 illustrates a block diagram of selected components of an examplemobile device 102, in accordance with embodiments of the presentdisclosure. As shown in FIG. 1, mobile device 102 may comprise anenclosure 101, a controller 103, a memory 104, a mechanical member 105,a microphone 106, a linear resonant actuator 107, a radiotransmitter/receiver 108, a speaker 110, and a resonant phase sensingsystem 112.

Enclosure 101 may comprise any suitable housing, casing, or otherenclosure for housing the various components of mobile device 102.Enclosure 101 may be constructed from plastic, metal, and/or any othersuitable materials. In addition, enclosure 101 may be adapted (e.g.,sized and shaped) such that mobile device 102 is readily transported ona person of a user of mobile device 102. Accordingly, mobile device 102may include but is not limited to a smart phone, a tablet computingdevice, a handheld computing device, a personal digital assistant, anotebook computer, a video game controller, or any other device that maybe readily transported on a person of a user of mobile device 102.

Controller 103 may be housed within enclosure 101 and may include anysystem, device, or apparatus configured to interpret and/or executeprogram instructions and/or process data, and may include, withoutlimitation a microprocessor, microcontroller, digital signal processor(DSP), application specific integrated circuit (ASIC), or any otherdigital or analog circuitry configured to interpret and/or executeprogram instructions and/or process data. In some embodiments,controller 103 may interpret and/or execute program instructions and/orprocess data stored in memory 104 and/or other computer-readable mediaaccessible to controller 103.

Memory 104 may be housed within enclosure 101, may be communicativelycoupled to controller 103, and may include any system, device, orapparatus configured to retain program instructions and/or data for aperiod of time (e.g., computer-readable media). Memory 104 may includerandom access memory (RAM), electrically erasable programmable read-onlymemory (EEPROM), a Personal Computer Memory Card InternationalAssociation (PCMCIA) card, flash memory, magnetic storage, opto-magneticstorage, or any suitable selection and/or array of volatile ornon-volatile memory that retains data after power to mobile device 102is turned off.

Microphone 106 may be housed at least partially within enclosure 101,may be communicatively coupled to controller 103, and may comprise anysystem, device, or apparatus configured to convert sound incident atmicrophone 106 to an electrical signal that may be processed bycontroller 103, wherein such sound is converted to an electrical signalusing a diaphragm or membrane having an electrical capacitance thatvaries based on sonic vibrations received at the diaphragm or membrane.Microphone 106 may include an electrostatic microphone, a condensermicrophone, an electret microphone, a microelectromechanical systems(MEMS) microphone, or any other suitable capacitive microphone.

Radio transmitter/receiver 108 may be housed within enclosure 101, maybe communicatively coupled to controller 103, and may include anysystem, device, or apparatus configured to, with the aid of an antenna,generate and transmit radio-frequency signals as well as receiveradio-frequency signals and convert the information carried by suchreceived signals into a form usable by controller 103. Radiotransmitter/receiver 108 may be configured to transmit and/or receivevarious types of radio-frequency signals, including without limitation,cellular communications (e.g., 2G, 3G, 4G, LTE, etc.), short-rangewireless communications (e.g., BLUETOOTH), commercial radio signals,television signals, satellite radio signals (e.g., GPS), WirelessFidelity, etc.

A speaker 110 may be housed at least partially within enclosure 101 ormay be external to enclosure 101, may be communicatively coupled tocontroller 103, and may comprise any system, device, or apparatusconfigured to produce sound in response to electrical audio signalinput. In some embodiments, speaker 110 may comprise a dynamicloudspeaker, which employs a lightweight diaphragm mechanically coupledto a rigid frame via a flexible suspension that constrains a voice coilto move axially through a cylindrical magnetic gap. When an electricalsignal is applied to the voice coil, a magnetic field is created by theelectric current in the voice coil, making it a variable electromagnet.The voice coil and the driver's magnetic system interact, generating amechanical force that causes the voice coil (and thus, the attachedcone) to move back and forth, thereby reproducing sound under thecontrol of the applied electrical signal coming from the amplifier.

Mechanical member 105 may be housed within or upon enclosure 101, andmay include any suitable system, device, or apparatus configured suchthat all or a portion of mechanical member 105 displaces in positionresponsive to a force, a pressure, or a touch applied upon orproximately to mechanical member 105. In some embodiments, mechanicalmember 105 may be designed to appear as a mechanical button on theexterior of enclosure 101.

Linear resonant actuator 107 may be housed within enclosure 101, and mayinclude any suitable system, device, or apparatus for producing anoscillating mechanical force across a single axis. For example, in someembodiments, linear resonant actuator 107 may rely on an alternatingcurrent voltage to drive a voice coil pressed against a moving massconnected to a spring. When the voice coil is driven at the resonantfrequency of the spring, linear resonant actuator 107 may vibrate with aperceptible force. Thus, linear resonant actuator 107 may be useful inhaptic applications within a specific frequency range. While, for thepurposes of clarity and exposition, this disclosure is described inrelation to the use of linear resonant actuator 107, it is understoodthat any other type or types of vibrational actuators (e.g., eccentricrotating mass actuators) may be used in lieu of or in addition to linearresonant actuator 107. In addition, it is also understood that actuatorsarranged to produce an oscillating mechanical force across multiple axesmay be used in lieu of or in addition to linear resonant actuator 107.As described elsewhere in this disclosure, a linear resonant actuator107, based on a signal received from resonant phase sensing system 112,may render haptic feedback to a user of mobile device 102 for at leastone of mechanical button replacement and capacitive sensor feedback.

Together, mechanical member 105 and linear resonant actuator 107 mayform a human-interface device, such as a virtual interface (e.g., avirtual button), which, to a user of mobile device 102, has a look andfeel of a mechanical button or other mechanical interface of mobiledevice 102.

Resonant phase sensing system 112 may be housed within enclosure 101,may be communicatively coupled to mechanical member 105 and linearresonant actuator 107, and may include any system, device, or apparatusconfigured to detect a displacement of mechanical member 105 indicativeof a physical interaction (e.g., by a user of mobile device 102) withthe human-machine interface of mobile device 102 (e.g., a force appliedby a human finger to a virtual interface of mobile device 102). Asdescribed in greater detail below, resonant phase sensing system 112 maydetect displacement of mechanical member 105 by performing resonantphase sensing of a resistive-inductive-capacitive sensor for which animpedance (e.g., inductance, capacitance, and/or resistance) of theresistive-inductive-capacitive sensor changes in response todisplacement of mechanical member 105. Thus, mechanical member 105 maycomprise any suitable system, device, or apparatus which all or aportion thereof may displace, and such displacement may cause a changein an impedance of a resistive-inductive-capacitive sensor integral toresonant phase sensing system 112. Resonant phase sensing system 112 mayalso generate an electronic signal for driving linear resonant actuator107 in response to a physical interaction associated with ahuman-machine interface associated with mechanical member 105. Detail ofan example resonant phase sensing system 112 in accordance withembodiments of the present disclosure is depicted in greater detailbelow.

Although specific example components are depicted in FIG. 1 as beingintegral to mobile device 102 (e.g., controller 103, memory 104,mechanical member 105, microphone 106, radio transmitter/receiver 108,speakers(s) 110, linear resonant actuator 107, etc.), a mobile device102 in accordance with this disclosure may comprise one or morecomponents not specifically enumerated above. For example, although FIG.1 depicts certain user interface components, mobile device 102 mayinclude one or more other user interface components in addition to thosedepicted in FIG. 1, including but not limited to a keypad, a touchscreen, and a display, thus allowing a user to interact with and/orotherwise manipulate mobile device 102 and its associated components. Inaddition, although FIG. 1 depicts only a single virtual buttoncomprising mechanical member 105 and linear resonant actuator 107 forpurposes of clarity and exposition, in some embodiments a mobile device102 may have multiple virtual interfaces each comprising a respectivemechanical member 105 and linear resonant actuator 107.

Although, as stated above, resonant phase sensing system 112 may detectdisplacement of mechanical member 105 by performing resonant phasesensing of a resistive-inductive-capacitive sensor for which animpedance (e.g., inductance, capacitance, and/or resistance) of theresistive-inductive-capacitive sensor changes in response todisplacement of mechanical member 105, in some embodiments, resonantphase sensing system 112 may primarily detect displacement of mechanicalmember 105 by using resonant phase sensing to determine a change in aninductance of a resistive-inductive-capacitive sensor. For example,FIGS. 2 and 3 illustrate selected components of an example inductivesensing application that may be implemented by resonant phase sensingsystem 112, in accordance with embodiments of the present disclosure.

FIG. 2 illustrates mechanical member 105 embodied as a metal plateseparated by a distance d from an inductive coil 202, in accordance withembodiments of the present disclosure. FIG. 3 illustrates selectedcomponents of an inductive sensing system 300 that may be implemented byresonant phase sensing system 112, in accordance with embodiments of thepresent disclosure. As shown in FIG. 3, inductive sensing system 300 mayinclude mechanical member 105, modeled as a variable electricalresistance 304 and a variable electrical inductance 306, and may includeinductive coil 202 in physical proximity to mechanical member 105 suchthat inductive coil 202 has a mutual inductance with mechanical member105 defined by a variable coupling coefficient k. As shown in FIG. 3,inductive coil 202 may be modeled as a variable electrical inductance308 and a variable electrical resistance 310.

In operation, as a current I flows through inductive coil 202, suchcurrent may induce a magnetic field which in turn may induce an eddycurrent inside mechanical member 105. When a force is applied to and/orremoved from mechanical member 105, which alters distance d betweenmechanical member 105 and inductive coil 202, the coupling coefficientk, variable electrical resistance 304, and/or variable electricalinductance 306 may also change in response to the change in distance.These changes in the various electrical parameters may, in turn, modifyan effective impedance Z_(L) of inductive coil 202.

FIG. 4A illustrates a diagram of selected components of an exampleresonant phase sensing system 112A, in accordance with embodiments ofthe present disclosure. In some embodiments, resonant phase sensingsystem 112A may be used to implement resonant phase sensing system 112of FIG. 1. As shown FIG. 4A, resonant phase sensing system 112A mayinclude a resistive-inductive-capacitive sensor 402 and a processingintegrated circuit (IC) 412A.

As shown in FIG. 4A, resistive-inductive-capacitive sensor 402 mayinclude mechanical member 105, inductive coil 202, a resistor 404, andcapacitor 406, wherein mechanical member 105 and inductive coil 202 havea variable coupling coefficient k. Although shown in FIG. 4A to bearranged in parallel with one another, it is understood that inductivecoil 202, resistor 404, and capacitor 406 may be arranged in any othersuitable manner that allows resistive-inductive-capacitive sensor 402 toact as a resonant tank. For example, in some embodiments, inductive coil202, resistor 404, and capacitor 406 may be arranged in series with oneanother. In some embodiments, resistor 404 may not be implemented with astand-alone resistor, but may instead be implemented by a parasiticresistance of inductive coil 202, a parasitic resistance of capacitor406, and/or any other suitable parasitic resistance.

Processing IC 412A may be communicatively coupled toresistive-inductive-capacitive sensor 402 and may comprise any suitablesystem, device, or apparatus configured to implement a measurementcircuit to measure phase information associated withresistive-inductive-capacitive sensor 402 and based on the phaseinformation, determine a displacement of mechanical member 105 relativeto resistive-inductive-capacitive sensor 402. Thus, processing IC 412Amay be configured to determine an occurrence of a physical interaction(e.g., press or release of a virtual button) associated with ahuman-machine interface associated with mechanical member 105 based onthe phase information.

As shown in FIG. 4A, processing IC 412A may include a phase shifter 410,a voltage-to-current converter 408, a preamplifier 440, an intermediatefrequency mixer 442, a combiner 444, a programmable gain amplifier (PGA)414, a voltage-controlled oscillator (VCO) 416, a phase shifter 418, anamplitude and phase calculation block 431, a DSP 432, a low-pass filter434, and a combiner 450. Processing IC 412A may also include a coherentincident/quadrature detector implemented with an incident channelcomprising a mixer 420, a low-pass filter 424, and an analog-to-digitalconverter (ADC) 428, and a quadrature channel comprising a mixer 422, alow-pass filter 426, and an ADC 430 such that processing IC 412A isconfigured to measure the phase information using the coherentincident/quadrature detector.

Phase shifter 410 may include any system, device, or apparatusconfigured to detect an oscillation signal generated by processing IC412A (as explained in greater detail below) and phase shift suchoscillation signal (e.g., by 45 degrees) such that a normal operatingfrequency of resonant phase sensing system 112A, an incident componentof a sensor signal ϕ generated by pre-amplifier 440, is approximatelyequal to a quadrature component of sensor signal ϕ, so as to providecommon mode noise rejection by a phase detector implemented byprocessing IC 412A, as described in greater detail below.

Voltage-to-current converter 408 may receive the phase shiftedoscillation signal from phase shifter 410, which may be a voltagesignal, convert the voltage signal to a corresponding current signal,and drive the current signal on resistive-inductive-capacitive sensor402 at a driving frequency with the phase-shifted oscillation signal inorder to generate sensor signal ϕ which may be processed by processingIC 412A, as described in greater detail below. In some embodiments, adriving frequency of the phase-shifted oscillation signal may beselected based on a resonant frequency of resistive-inductive-capacitivesensor 402 (e.g., may be approximately equal to the resonant frequencyof resistive-inductive-capacitive sensor 402).

Preamplifier 440 may receive sensor signal ϕ and condition sensor signalϕ for frequency mixing, with mixer 442, to an intermediate frequency Δfcombined by combiner 444 with an oscillation frequency generated by VCO416, as described in greater detail below, wherein intermediatefrequency Δf is significantly less than the oscillation frequency. Insome embodiments, preamplifier 440, mixer 442, and combiner 444 may notbe present, in which case PGA 414 may receive sensor signal ϕ directlyfrom resistive-inductive-capacitive sensor 402. However, when present,preamplifier 440, mixer 442, and combiner 444 may allow for mixingsensor signal ϕ down to a lower intermediate frequency Δf which mayallow for lower-bandwidth and more efficient ADCs (e.g., ADCs 428 and430 of FIGS. 4A and 4B and ADC 429 of FIG. 4C, described below) and/orwhich may allow for minimization of phase and/or gain mismatches in theincident and quadrature paths of the phase detector of processing IC412A.

In operation, PGA 414 may further amplify sensor signal ϕ to conditionsensor signal ϕ for processing by the coherent incident/quadraturedetector. VCO 416 may generate an oscillation signal to be used as abasis for the signal driven by voltage-to-current converter 408, as wellas the oscillation signals used by mixers 420 and 422 to extractincident and quadrature components of amplified sensor signal ϕ. Asshown in FIG. 4A, mixer 420 of the incident channel may use an unshiftedversion of the oscillation signal generated by VCO 416, while mixer 422of the quadrature channel may use a 90-degree shifted version of theoscillation signal phase shifted by phase shifter 418. As mentionedabove, the oscillation frequency of the oscillation signal generated byVCO 416 may be selected based on a resonant frequency ofresistive-inductive-capacitive sensor 402 (e.g., may be approximatelyequal to the resonant frequency of resistive-inductive-capacitive sensor402).

In the incident channel, mixer 420 may extract the incident component ofamplified sensor signal 4, low-pass filter 424 may filter out theoscillation signal mixed with the amplified sensor signal ϕ to generatea direct current (DC) incident component, and ADC 428 may convert suchDC incident component into an equivalent incident component digitalsignal for processing by amplitude and phase calculation block 431.Similarly, in the quadrature channel, mixer 422 may extract thequadrature component of amplified sensor signal ϕ, low-pass filter 426may filter out the phase-shifted oscillation signal mixed with theamplified sensor signal ϕ to generate a direct current (DC) quadraturecomponent, and ADC 430 may convert such DC quadrature component into anequivalent quadrature component digital signal for processing byamplitude and phase calculation block 431.

Amplitude and phase calculation block 431 may include any system,device, or apparatus configured to receive phase information comprisingthe incident component digital signal and the quadrature componentdigital signal and based thereon, extract amplitude and phaseinformation.

DSP 432 may include any system, device, or apparatus configured tointerpret and/or execute program instructions and/or process data. Inparticular, DSP 432 may receive the phase information and the amplitudeinformation generated by amplitude and phase calculation block 431 andbased thereon, determine a displacement of mechanical member 105relative to resistive-inductive-capacitive sensor 402, which may beindicative of an occurrence of a physical interaction (e.g., press orrelease of a virtual button or other interaction with a virtualinterface) associated with a human-machine interface associated withmechanical member 105 based on the phase information. DSP 432 may alsogenerate an output signal indicative of the displacement. In someembodiments, such output signal may comprise a control signal forcontrolling mechanical vibration of linear resonant actuator 107 inresponse to the displacement. Further, as described in greater detailbelow, DSP 432 may be configured to perform functionality for maximizingdynamic range of resonant phase sensing system 112A.

The phase information generated by amplitude and phase calculation block431 may be subtracted from a reference phase ϕ_(ref) by combiner 450 inorder to generate an error signal that may be received by low-passfilter 434. Low-pass filter 434 may low-pass filter the error signal,and such filtered error signal may be applied to VCO 416 to modify thefrequency of the oscillation signal generated by VCO 416, in order todrive sensor signal ϕ towards reference phase ϕ_(ref) As a result,sensor signal ϕ may comprise a transient decaying signal in response toa “press” of a virtual button (or other interaction with a virtualinterface) associated with resonant phase sensing system 112A as well asanother transient decaying signal in response to a subsequent “release”of the virtual button (or other interaction with a virtual interface).Accordingly, low-pass filter 434 in connection with VCO 416 mayimplement a feedback control loop that may track changes in operatingparameters of resonant phase sensing system 112A by modifying thedriving frequency of VCO 416.

FIG. 4B illustrates a diagram of selected components of an exampleresonant phase sensing system 112B, in accordance with embodiments ofthe present disclosure. In some embodiments, resonant phase sensingsystem 112B may be used to implement resonant phase sensing system 112of FIG. 1. Resonant phase sensing system 112B of FIG. 4B may be, in manyrespects, similar to resonant phase sensing system 112A of FIG. 4A.Accordingly, only those differences between resonant phase sensingsystem 112B and resonant phase sensing system 112A may be describedbelow. As shown FIG. 4B, resonant phase sensing system 112B may includeprocessing IC 412B in lieu of processing IC 412A. Processing IC 412B ofFIG. 4B may be, in many respects, similar to processing IC 412A of FIG.4A. Accordingly, only those differences between processing IC 412B andprocessing IC 412A may be described below.

Processing IC 412B may include fixed-frequency oscillator 417 andvariable phase shifter 419 in lieu of VCO 416 of processing IC 412A.Thus, in operation, oscillator 417 may drive a fixed driving signal andoscillation signal which variable phase shifter 419 may phase shift togenerate oscillation signals to be mixed by mixers 420 and 422. Similarto that of processing IC 412A, low-pass filter 434 may low-pass filteran error signal based on phase information extracted by amplitude andphase calculation block 431, but instead such filtered error signal maybe applied to variable phase shifter 419 to modify the phase offset ofthe oscillation signal generated by oscillator 417, in order to drivesensor signal ϕ towards indicating a phase shift of zero. As a result,sensor signal ϕ may comprise a transient decaying signal in response toa “press” of a virtual button (or other interaction with a virtualinterface) associated with resonant phase sensing system 112B as well asanother transient decaying signal in response to a subsequent “release”of the virtual button (or other interaction with a virtual interface).Accordingly, low-pass filter 434 in connection with variable phaseshifter 419 may implement a feedback control loop that may track changesin operating parameters of resonant phase sensing system 112B bymodifying the phase shift applied by variable phase shifter 419.

FIG. 4C illustrates a diagram of selected components of an exampleresonant phase sensing system 112C, in accordance with embodiments ofthe present disclosure. In some embodiments, resonant phase sensingsystem 112C may be used to implement resonant phase sensing system 112of FIG. 1. Resonant phase sensing system 112C of FIG. 4C may be, in manyrespects, similar to resonant phase sensing system 112A of FIG. 4A.Accordingly, only those differences between resonant phase sensingsystem 112C and resonant phase sensing system 112A may be describedbelow. For example, a particular difference between resonant phasesensing system 112C and resonant phase sensing system 112A is thatresonant phase sensing system 112C may include ADC 429 in lieu of ADC428 and ADC 430. Accordingly, a coherent incident/quadrature detectorfor resonant phase sensing system 112C may be implemented with anincident channel comprising a digital mixer 421 and a digital low-passfilter 425 (in lieu of analog mixer 420 and analog low-pass filter 424)and a quadrature channel comprising a digital mixer 423 and a low-passfilter 427 (in lieu of analog mixer 422 and analog low-pass filter 426)such that processing IC 412C is configured to measure the phaseinformation using such coherent incident/quadrature detector. Althoughnot explicitly shown, resonant phase sensing system 112B could bemodified in a manner similar to that of how resonant phase sensingsystem 112A is shown to be modified to result in resonant phase sensingsystem 112C.

FIG. 5 illustrates a diagram of selected components of an exampleresonant phase sensing system 112D implementing time-divisionmultiplexed processing of multiple resistive-inductive-capacitivesensors 402 (e.g., resistive-inductive-capacitive sensors 402A-402Nshown in FIG. 5), in accordance with embodiments of the presentdisclosure. In some embodiments, resonant phase sensing system 112D maybe used to implement resonant phase sensing system 112 of FIG. 1.Resonant phase sensing system 112D of FIG. 5 may be, in many respects,similar to resonant phase sensing system 112A of FIG. 4A. Accordingly,only those differences between resonant phase sensing system 112D andresonant phase sensing system 112A may be described below. Inparticular, resonant phase sensing system 112D may include a pluralityof resistive-inductive-capacitive sensors 402 (e.g.,resistive-inductive-capacitive sensors 402A-402N shown in FIG. 5) inlieu of the single resistive-inductive-capacitive sensor 402 shown inFIG. 4A. In addition, resonant phase sensing system 112D may includemultiplexers 502 and 504, each of which may select an output signal froma plurality of input signals responsive to a control signal SELECT(which may be controlled by a time-division multiplexing controlsubsystem implemented by controller 103 or another suitable component ofmobile device 102). Thus, while in some embodiments a device such asmobile device 102 may comprise a plurality ofresistive-inductive-capacitive sensors 402 which may be simultaneouslydriven and separately processed by a respective processing IC, in otherembodiments a resonant phase sensing system (e.g., resonant phasesensing system 112D) may drive resistive-inductive-capacitive sensors402 in a time-division multiplexed manner Such approach may reduce powerconsumption and device size as compared with multiple-sensorimplementations in which the multiple sensors are simultaneously drivenand/or sensed. Device size may be reduced by time-division multiplexingmultiple sensors into a single driver and measurement circuit channel,wherein only a single driver and a single measurement circuit may berequired, thus minimizing an amount of integrated circuit area needed toperform driving and measurement. In addition, by leveraging a singledriver and measurement circuit, no calibration may be needed to adjustfor mismatches and/or errors between different drivers and/or differentmeasurement circuits.

For purposes of clarity and exposition, preamplifier 440, mixer 442, andcombiner 444 have been excluded from FIG. 5. However, in someembodiments, processing IC 412D may include preamplifier 440, mixer 442,and combiner 444 similar to that depicted in FIGS. 4A-4C.

In resonant phase sensing system 112D, when a firstresistive-inductive-capacitive sensor (e.g.,resistive-inductive-capacitive sensor 402A) is selected by thetime-division multiplexing control subsystem for being driven byvoltage-to-current converter 408 and measured by the measurement circuitimplemented by processing IC 412A, other resistive-inductive-capacitivesensors (e.g., resistive-inductive-capacitive sensors 402B-402N) mayeach be placed in a low-impedance state. Similarly, when a secondresistive-inductive-capacitive sensor (e.g.,resistive-inductive-capacitive sensor 402B) is selected by thetime-division multiplexing control subsystem for being driven byvoltage-to-current converter 408 and measured by the measurement circuitimplemented by processing IC 412A, other resistive-inductive-capacitivesensors (e.g., resistive-inductive-capacitive sensors other than 402B,including 402A) may each be placed in a low-impedance state. Such anapproach may minimize power consumption within unselectedresistive-inductive-capacitive sensors 402.

Although not explicitly shown, resonant phase sensing system 112B couldbe modified in a manner similar to that of how resonant phase sensingsystem 112A is shown to be modified to result in resonant phase sensingsystem 112D, such that resonant phase sensing system 112B couldimplement time-division multiplexed sensing on a plurality ofresistive-inductive-capacitive sensors 402. Similarly, although notexplicitly shown, resonant phase sensing system 112C could be modifiedin a manner similar to that of how resonant phase sensing system 112A isshown to be modified to result in resonant phase sensing system 112D,such that resonant phase sensing system 112C could implementtime-division multiplexed sensing on a plurality ofresistive-inductive-capacitive sensors 402.

As mentioned above, DSP 432 as shown in any of resonant phase sensingsystems 112A-112D may be configured to perform functionality formaximizing a dynamic range of such resonant phase sensing systems112A-112D. To illustrate, FIG. 6 shows graphs depicting exampleamplitude-versus-frequency and phase-versus-frequency characteristics ofa resonant sensor, such as that used in resonant phase sensing systems112A-112D, in accordance with embodiments of the present disclosure. Ascontemplated above, displacement of mechanical member 105 may lead tochanges in resonant characteristics of resistive-inductive-capacitivesensor 402, including a change in a resonant frequency ofresistive-inductive-capacitive sensor 402. As shown in FIG. 6, for smallsignal deviations at or near a baseline resonant frequency f₀ (e.g., noforce applied to mechanical member 105), the phase information generatedby amplitude and phase calculation block 431 may have more sensitivitythan the amplitude information generated by amplitude and phasecalculation block 431. However, for larger signal deviations frombaseline resonant frequency f₀, the phase response may lose sensitivityand may become almost flat. While such narrow range of phase sensitivitymay be suitable for certain types of button-press applications that mayhave only a small sensor displacement, other applications may requireaccurate sensing of larger sensor displacements without compromisingsmall-signal sensitivity.

To provide such desired dynamic range, DSP 432 may be configured tocalculate displacement based on phase information for small signallevels in order to retain desired sensitivity in a range of frequencies(corresponding to a range of displacements) within a first predefineddeviation from baseline resonant frequency f₀, as depicted by region Ain FIG. 6. However, DSP 432 may also be configured to calculatedisplacement based on amplitude information for large signal levelsbeyond a second predefined deviation from baseline resonant frequencyf₀, as depicted by regions C in FIG. 6. In a range of frequenciesbetween the first predefined deviation and second predefined deviation,as depicted by regions B in FIG. 6, DSP 432 may further be configured todynamically transition between phase-based sensing and amplitude-basedsensing using a weighted combination of the phase information and theamplitude information, starting with 100% weighting of phase informationat the first predefined deviation and transitioning to 100% weighting ofthe amplitude information at the second predefined deviation. In someembodiments, DSP 432 may be configured to set the transition regions B(e.g., set the first predefined deviation and/or the second predefineddeviation) based on a quality factor of resistive-inductive-capacitivesensor 402. In certain of such embodiments, DSP 432 may further beconfigured to periodically update transition regions B based onreal-time measurements of quality factor and/or resonant frequency.

Accordingly, resonant phase sensing systems 112A-112D may each comprisea resonant sensing system configured to process both phase informationand amplitude information in response to changes in an impedance (e.g.,inductance) of a resonant sensor, wherein such resonant sensing systemincludes a selection engine (e.g., implemented by DSP 432) thatdynamically selects among using phase, using amplitude, or using acombination of phase and amplitude to detect a change in the impedanceof the resonant sensor based on one or more criteria. The criteria mayinclude a quality factor of the resonant sensor, a resonant frequency ofthe sensor, and/or threshold levels (e.g., first predefined deviation,second predefined deviation) based on one or both of the quality factorand/or the resonant frequency.

In some embodiments, DSP 432 may further be configured to use amplitudeinformation as a supplement to phase information in the event of a faultin phase sensing (e.g., signal interference and/or malfunction) inregion A. Likewise, DSP 432 may further be configured to use phaseinformation as a supplement to amplitude information in the event of afault in amplitude sensing (e.g., signal interference and/ormalfunction) in regions C.

Alternatively to the approach described above relating to dynamicallytransitioning between phase-based and amplitude-based sensing, in otherembodiments, DSP 432 may be configured to dynamically modify aneffective quality factor of resistive-inductive-capacitive sensor 402 tomaximize dynamic range while maintaining small-signal sensitivity. Forexample, as a signal increases (e.g., frequency deviation from baselineresonant frequency f₀ increases), DSP 432 may decrease a quality factorof resistive-inductive-capacitive sensor 402, which may have the effectof extending the linear/monotonic portion of the phase-response curve.Similarly, as a signal decreases (e.g., frequency deviation frombaseline resonant frequency f₀ decreases), DSP 432 may increase aquality factor of resistive-inductive-capacitive sensor 402 back to anominal level. In some embodiments, DSP 432 may employ thresholds basedon the nominal quality factor of resistive-inductive-capacitive sensor402 to determine when to modify the effective quality factor ofresistive-inductive-capacitive sensor 402. In some of such embodiments,DSP 432 may use multiple discrete steps and/or analog tuning to achievea range of effective quality factors for resistive-inductive-capacitivesensor 402. FIG. 7 depicts an example of an approach for modifying theeffective quality factor of resistive-inductive-capacitive sensor 402.

FIG. 7 illustrates a diagram of selected components of an exampleresonant phase sensing system 112E, in accordance with embodiments ofthe present disclosure. In some embodiments, resonant phase sensingsystem 112E may be used to implement resonant phase sensing system 112of FIG. 1. Resonant phase sensing system 112E of FIG. 7 may be, in manyrespects, similar to resonant phase sensing system 112A of FIG. 4A.Accordingly, only those differences between resonant phase sensingsystem 112E and resonant phase sensing system 112A may be describedbelow. As shown in FIG. 7, resonant phase sensing system 112E mayinclude processing IC 412E in lieu of processing IC 412A. Processing IC412E of FIG. 7 may be, in many respects, similar to processing IC 412Aof FIG. 4A. Accordingly, only those differences between processing IC412E and processing IC 412A may be described below. In particular,processing IC 412E may include a variable resistor 452 placed inparallel with inductive coil 202 and capacitor 406 ofresistive-inductive-capacitive sensor 402. Accordingly, to modify aneffective quality factor of resistive-inductive-capacitive sensor 402,DSP 432 may vary a resistance of variable resistor 452.

In addition to the approach depicted in FIG. 7, other approaches may beused to modify an effective quality factor ofresistive-inductive-capacitive sensor 402. For example, in someembodiments, DSP 432 may modify the effective quality factor ofresistive-inductive-capacitive sensor 402 via a variable resistor inseries with inductive coil 202.

As used herein, when two or more elements are referred to as “coupled”to one another, such term indicates that such two or more elements arein electronic communication or mechanical communication, as applicable,whether connected indirectly or directly, with or without interveningelements.

This disclosure encompasses all changes, substitutions, variations,alterations, and modifications to the example embodiments herein that aperson having ordinary skill in the art would comprehend. Similarly,where appropriate, the appended claims encompass all changes,substitutions, variations, alterations, and modifications to the exampleembodiments herein that a person having ordinary skill in the art wouldcomprehend. Moreover, reference in the appended claims to an apparatusor system or a component of an apparatus or system being adapted to,arranged to, capable of, configured to, enabled to, operable to, oroperative to perform a particular function encompasses that apparatus,system, or component, whether or not it or that particular function isactivated, turned on, or unlocked, as long as that apparatus, system, orcomponent is so adapted, arranged, capable, configured, enabled,operable, or operative. Accordingly, modifications, additions, oromissions may be made to the systems, apparatuses, and methods describedherein without departing from the scope of the disclosure. For example,the components of the systems and apparatuses may be integrated orseparated. Moreover, the operations of the systems and apparatusesdisclosed herein may be performed by more, fewer, or other componentsand the methods described may include more, fewer, or other steps.Additionally, steps may be performed in any suitable order. As used inthis document, “each” refers to each member of a set or each member of asubset of a set.

Although exemplary embodiments are illustrated in the figures anddescribed below, the principles of the present disclosure may beimplemented using any number of techniques, whether currently known ornot. The present disclosure should in no way be limited to the exemplaryimplementations and techniques illustrated in the drawings and describedabove.

Unless otherwise specifically noted, articles depicted in the drawingsare not necessarily drawn to scale.

All examples and conditional language recited herein are intended forpedagogical objects to aid the reader in understanding the disclosureand the concepts contributed by the inventor to furthering the art, andare construed as being without limitation to such specifically recitedexamples and conditions. Although embodiments of the present disclosurehave been described in detail, it should be understood that variouschanges, substitutions, and alterations could be made hereto withoutdeparting from the spirit and scope of the disclosure.

Although specific advantages have been enumerated above, variousembodiments may include some, none, or all of the enumerated advantages.Additionally, other technical advantages may become readily apparent toone of ordinary skill in the art after review of the foregoing figuresand description.

To aid the Patent Office and any readers of any patent issued on thisapplication in interpreting the claims appended hereto, applicants wishto note that they do not intend any of the appended claims or claimelements to invoke 35 U.S.C. § 112(f) unless the words “means for” or“step for” are explicitly used in the particular claim.

What is claimed is:
 1. A system comprising: a resistive-inductive-capacitive sensor configured to sense a physical quantity; and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to: measure one or more resonance parameters associated with the resistive-inductive-capacitive sensor and indicative of the physical quantity; and in order to maximize dynamic range in determining the physical quantity from the one or more resonance parameters, dynamically modify, across the dynamic range, either of: reliance on the one or more resonance parameters in determining the physical quantity; or one or more resonance properties of the resistive-inductive-capacitive sensor.
 2. The system of claim 1, wherein: the one or more resonance parameters include phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor; and the measurement circuit is further configured to dynamically modify reliance on the one or more resonance parameters in determining the physical quantity, wherein dynamically modifying reliance on the one or more resonance parameters in determining the physical quantity comprises dynamically selecting, based on one or more criteria, among using the phase information, the amplitude information, and a combination of the phase information and the amplitude information to determine the physical quantity.
 3. The system of claim 2, wherein the one or more criteria includes one or more of a quality factor of the resistive-inductive-capacitive sensor and a baseline resonant frequency of the resistive-inductive-capacitive sensor.
 4. The system of claim 2, wherein the one or more criteria comprises one or more thresholds relative to a deviation from either of a quality factor of the resistive-inductive-capacitive sensor and a baseline resonant frequency of the resistive-inductive-capacitive sensor.
 5. The system of claim 4, wherein: the measurement circuit determines the physical quantity based on the phase information when the deviation is less than a first threshold; the measurement circuit determines the physical quantity based on the amplitude information when the deviation is more than a second threshold; and the measurement circuit determines the physical quantity based on a weighted average of the phase information and the amplitude information when the deviation is more than the first threshold and less than the second threshold, transitioning a relative weight of the phase information and the amplitude information between the first threshold and the second threshold.
 6. The system of claim 5, wherein the measurement circuit is further configured to: supplement the phase information with the amplitude information in determining the physical quantity when the deviation is less than the first threshold and a fault exists in measuring the phase information; and supplement the amplitude information with the phase information in determining the physical quantity when the deviation is more than the second threshold and a fault exists in measuring the amplitude information.
 7. The system of claim 1, wherein: the one or more resonance properties include a quality factor associated with the resistive-inductive-capacitive sensor; and the measurement circuit is further configured to dynamically modify the quality factor as a function of a deviation from either of the quality factor of the resistive-inductive-capacitive sensor and a baseline resonant frequency of the resistive-inductive-capacitive sensor.
 8. The system of claim 1, wherein the measurement circuit is further configured to determine a displacement of a mechanical member relative to the resistive-inductive-capacitive sensor based on the physical quantity, wherein the displacement of the mechanical member causes a change in an impedance of the resistive-inductive-capacitive sensor.
 9. The system of claim 1, wherein the physical quantity is indicative of user interaction with a human-machine interface.
 10. The system of claim 1, wherein the physical quantity is indicative of a displacement of a mechanical member relative to the resonant sensor.
 11. A method comprising: measuring one or more resonance parameters associated with a resistive-inductive-capacitive sensor and indicative of a physical quantity sensed by the resistive-inductive-capacitive sensor; and in order to maximize dynamic range in determining the physical quantity from the one or more resonance parameters, dynamically modifying, across the dynamic range, either of: reliance on the one or more resonance parameters in determining the physical quantity; or one or more resonance properties of the resistive-inductive-capacitive sensor.
 12. The method of claim 11, wherein: the one or more resonance parameters include phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor; and the measurement circuit is further configured to dynamically modify reliance on the one or more resonance parameters in determining the physical quantity, wherein dynamically modifying reliance on the one or more resonance parameters in determining the physical quantity comprises dynamically selecting, based on one or more criteria, among using the phase information, the amplitude information, and a combination of the phase information and the amplitude information to determine the physical quantity.
 13. The method of claim 12, wherein the one or more criteria includes one or more of a quality factor of the resistive-inductive-capacitive sensor and a baseline resonant frequency of the resistive-inductive-capacitive sensor.
 14. The method of claim 12, wherein the one or more criteria comprises one or more thresholds relative to a deviation from either of a quality factor of the resistive-inductive-capacitive sensor and a baseline resonant frequency of the resistive-inductive-capacitive sensor.
 15. The method of claim 14, wherein: the measurement circuit determines the physical quantity based on the phase information when the deviation is less than a first threshold; the measurement circuit determines the physical quantity based on the amplitude information when the deviation is more than a second threshold; and the measurement circuit determines the physical quantity based on a weighted average of the phase information and the amplitude information when the deviation is more than the first threshold and less than the second threshold, transitioning a relative weight of the phase information and the amplitude information between the first threshold and the second threshold.
 16. The method of claim 15, wherein the measurement circuit is further configured to: supplement the phase information with the amplitude information in determining the physical quantity when the deviation is less than the first threshold and a fault exists in measuring the phase information; and supplement the amplitude information with the phase information in determining the physical quantity when the deviation is more than the second threshold and a fault exists in measuring the amplitude information.
 17. The method of claim 11, wherein: the one or more resonance properties include a quality factor associated with the resistive-inductive-capacitive sensor; and the measurement circuit is further configured to dynamically modify the quality factor as a function of a deviation from either of the quality factor of the resistive-inductive-capacitive sensor and a baseline resonant frequency of the resistive-inductive-capacitive sensor.
 18. The method of claim 11, wherein the measurement circuit is further configured to determine a displacement of a mechanical member relative to the resistive-inductive-capacitive sensor based on the physical quantity, wherein the displacement of the mechanical member causes a change in an impedance of the resistive-inductive-capacitive sensor.
 19. The method of claim 11, wherein the physical quantity is indicative of user interaction with a human-machine interface.
 20. The method of claim 11, wherein the physical quantity is indicative of a displacement of a mechanical member relative to the resonant sensor. 